The unidentified craft was brought down by warplanes approximately three kilometres (1.9 miles) from the border.

A source in the American government told Reuters that the craft was believed to be Russian, but the Kremlin denied the claim.

A statement from the country's military said it has issued three warnings before taking action, in line with NATO rules of engagement.

The news comes as a military source revealed "hundreds" of troops from Hezbollah and Iran have been sent to fight alongside the country's army against rebel forces in Aleppo – the country's second city.

President Bashar Assad's military offensive has been backed by Russian air strikes.

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EMERGENCY: Turkish fighter jets in action

NATO has blasted Russia in recent weeks after two of its jets made incursions into Turkish airspace.

Turkey has warned it will respond if the violations continue, and also complained that unidentified aircraft and Syria-based missile air defence systems are harassing its warplanes.

Reports suggest that the downed craft may have been a drone.

Igor Konashenkov, a spokesman for the Russian defense ministry, told Russian news agencies Friday that all Russian jets have safely returned to their base.